Technical Field
The present invention relates to a blow molding method that includes a primary blow molding step and a secondary blow molding step, a blow mold, a blow-molded container, and the like.
Background Art
A blow molding method that includes a primary blow molding step and a secondary blow molding step, a blow mold used for the blow molding method, and a blow-molded container obtained using the blow molding method are disclosed in Patent Documents 1 and 2, for example. The blow molding method blow-molds and expands a preform heated to an optimum stretch temperature in a heated primary blow mold into an intermediate molded article. The intermediate molded article is heated in the primary blow mold, and removed from the primary blow mold. The intermediate molded article that has shrunken and softened is blow-molded and expanded again in a secondary blow mold into a final molded article. A heat-resistant container is thus obtained. The primary blow mold used for the blow molding method is heated, and the secondary blow mold is heated at a low temperature as compared with the primary blow mold, or maintained at room temperature.
Patent Documents 3 to 5 disclose a method that blow-molds a preform in a blow mold so that a thread is formed in an intermediate area of the resulting blow-molded container, and removes the part of the blow-molded container that is situated on the side of the opening with respect to the thread to produce a wide-mouth container.